Alternating current switch mechanism



Dec 1936. J. F. FRESE ALTERNATING CURRENT SWITCH MECHANISM 2 Sheets-Sheet 1 Filed June 19, 1934 Dec. 22, 1936.

J. F. FRESE ALTERNATING CURRENT SWITCH MECHANISM Filed June 19,1934 2 Sheets-Sheet 2 Patented Dec. 22, 1936 UNITED STATES PATENT OFFICE ALTERNATING CURRENT SWITCH MECHANISM poration of Maryland Application June 19, 1934, Serial No. 131,351

4 Claims.

This invention relates to electro-magneticaliy operated switches or contactors adapted for use on alternating electric current systems for connecting loads, such as motors, to the power lines.

In switches of this kind the magnet for closing the switch usually has a coil wound to take a considerable amount of current for a short time, in order that the magnet may attract its armature with sufllcient force to close the switch promptly and firmly, after which the current flow through the magnet coil is reduced in order to avoid injury to the coil. In accordance with the present invention, after the main magnet has moved its armature to the switch-closing position, the armature is locked in that'position by a latch which is controlled by a smaller holding magnet having a winding which takes but a small amount of current and which cannot be injured by the continued flow of such current therethrough, and simultaneously with the locking of the armature the current through the coil of the main magnet is automatically cut off, so that no injury to the latter coil can occur. The invention embodies features of construction and circuit arrange- 5 ments, all of which will be clear from the following specification, taken in connection with the accompanying drawings.

In the accompanying drawings,

Fig. 1 is a front elevation of a switch mechanism embodying my invention;

Fig. 2 is a side elevation of the same, looking from right to left in Fig. 1;

Fig. 3 is a central vertical section on the line 3-3 of Fig. 1; 35 Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 3;

Fig. 6 is a section on the line 5-6 of Fig. 2; and,

Fig. '7 is a diagrammatic view, showing the circuits.

40 Referring to the drawings, a indicates a suitable base of insulating material upon which the switch mechanism is mounted, b indicates a shaft, angular in cross-section which is journaled in brackets l and 2, this shaft, having a covering of 45 insulating material 3, and secured to the insulated portion of the shaft are switch arms 4, ,5 and 6. A main magnet c is mounted on the switch base above the rock shaft and an armature I, movable by this magnet, is secured to the rock shaft by 0 side plates 8, which project below the armature. The armature swings in a vertical plane and when attracted by the magnet the shaft is rocked to move the switch arms 4, 5 and 6 to closed positionsand in so doing springs 4 5 and 6 are compl essed, applying a yielding tension to the contact members of the switch. When the magnet is de-energized the springs rock the shaft and give the armature an initial impetus away from the magnet and it moves outward to the position shown in Fig. 2, wherein it is stopped by a latch d having a roller 9 which engages the upturned end [0 of a metal strip l0 mounted upon the upper end of the armature I. This strip extends downwardly for a short distance on the front side of the armature and has side flanges Hi by which it is secured to the armature. Above the flanges the strip extends rearwardly over the end of the armature and then curves upwardly at the rear of the roller, as shown in Fig. 2. When the armature is attracted to the magnet, the roller rides on the strip I0 and drops down in front of the armature, as shown in Fig. 3 and as hereinafter explained. The armature 1 actuates a normally open switch s and closes this switch when the armature is attracted by the magnet. This switch is in a control circuit for the magnets, as hereinafter explained. It comprises a springpressed contact member I I mounted upon a piece of insulating material l2 which is attached to the side plates 8 of the armature and this member ll serves as 'a bridge-piece to electrically conrect stationary contacts l3 and I4, attached to the base a.

The latch d comprises two parallel metal strips l5 connected together by cross-pins l6 and H. The rear ends l5 of the strips are inclined downwardly and pivotally connected, as indicated at l8, to upward extensions IQ of the side plates of the magnet c. A holding magnet e is secured to the base a above the latch and the I armature 20 of this magnet is pivoted at 2| in brackets 22 which depend from the magnet frame. A forked arm 23 secured to the armature, so as to rock therewith, engages the crosspin ll of the latch d. In the operation of the mechanism, the main and holding magnets are simultaneously energized and the armatures are attracted to the vertical positions shown in Fig. 3. While moving to these positions, the armature 20, through the forked arm 23, tends to rock the latch about the pivot l8, and when the armature I is in the vertical position, the forward end of the latch is forced downwardly in front of the upper end of the armature as shown in Fig. 3, and as long as the holding magnet is energized, the armature of the main magnet will be locked in this position. When the magnets are de-energized, the armature of the holding magnet is moved away from the magnet by springs 24 which are coiled about spools on the pivot pin 2! and during this movement the forked arm 23 rocks the latch about its pivotal axis and the forward end of the latch moves up Ward, releasing the armature l of the main magnet. This latter armature then swings forward until the upturned end H] of the metal strip ID engages the roller on the latch, as illustratedin Fig. 2.

The circuit of the main magnet extends through a switch t which is closed when the -latch is in normal position, shown in Fig. 2,

and is opened when the latch moves to the locking position, shown in Fig. 3. This switch comprises two parallel switch fingers 25 and .26 which bear upon contact pieces 21 and 28, respectively, mounted upon the ends of a piece of insulating material 28, arranged transversely of the latch near its forward end. The contact pieces are secured in place by a metal pin 30 which extends longitudinally through the insulation and engages both of the contact pieces, thus electrically connecting them together. Metal supports 3| and 32 for the contact fingers 25 and 26, respectively, are secured to the base a. The support 3| consists of a horizontally arranged metal strip having an offset end 3| by which it is secured to the base a, and the finger 25 has side flanges guided in its upward and downward movements on this strip. The supporting strip 32 for the finger 26 is the same as the strip 3|. Each finger is pressed toward thestrip upon which it is mounted by a spring 33 coiled about pin 34 which passes through an opening in the finger and into the support. When the armatures are in the positions shown in Fig. 2, the spring-pressed fingers are raised above the plane of the supporting strips, as shown-in Fig. 2, and when the armatures move to the positions shown in Fig. 3, the springpressed fingers follow the contact pieces 2'! and 28 downward, until the fingers rest fiat on the supports and then the further downward movement of the latch opens the switch d, as illustrated in Fig. 3.

The diagram, Fig. 7, shows the arrangement of circuits by which the magnets are controlled. The reference numerals 35, 36 and 31 represent supply wires leading from a three-phase alternating current source. A conductor 38 leads from.conductor 35 to the coil 39 of the main magnet c, thence by conductor 40 to and through switch t, which is normally closed, thence by conductor M to a normally closed push-button switch 42, thence by conductor 43 to normally open push-button switch 44, and thence by conductor 45 to the side 3'! of the supply circuit. The circuit for the holding magnet extends from the conductor 38 by way of connection 46 to the coil 41 of said magnet, and thence by conductor 48 to the conductor 4|, which leads from the main switch magnet to the closed and open push button switches and to the supply wire 31, as before described. Thus the coils of the magnets are connected in parallel so that upon the closure of the push-button switch 44 both magnets will be simultaneously energized. When the main magnet is energized its armature closes the switch .9 which shunts the push-button switch through conductors 49 and 50, so that the circuit through the coils of both magnets will be maintained after the release of the normally open push-button switch. The armature of the main magnet will also rock the shaft 3 to close the contactor switches 4, and 6. Simultaneously with the movement of the armatures toward their respective magnets, the latch will drop down, as shown in Fig. 3, and open the switch it which will interrupt the circuit through the coil of the main magnet and since the circuit of the holding magnet will not be interrupted but will be maintained through the switch s, the holding magnet, which takes but a small quantity of current, will hold the latch in the locking position until the normally closed switch 42 is opened. When this switch is opened the circuit through the coil of the holding magnet will be interrupted and the armature 20 will rock to normal position. In doing so the latch will be lifted, releasing the armature of the main magnet and closing the switch t. The armature of the main magnet, in returning to normal position, will open the switch s so that the parts will all be in position for the next operation.

It is to be noted that the latch cannot drop down until the armature of the main magnet moves from under the roller to the vertical position and that the switch t, which controls the circuit through the coil of the main magnet, cannot be opened until the latch has moved downward a certain distance in front of the armature, because the spring fingers 01' said switch follow down with the latch until they rest on their horizontal supports.

What I claim is:

1. Alternating current switch mechanism comprising a switch, a main magnet having a pivoted armature movable by said magnet to close the switch, a pivoted latch adapted to engage and lock said armature in its switch-closing position, a holding magnet having an armature, pivoted independently of the latch, adapted to move the latch into the locking position when the magnets are energized and. out

of locking position when the holding magnet is de-energized, and a switch operated by said latch for opening the circuit of the main magnet when the latch is moved to locking position.

2. Alternating current switch mechanism comprising a normally open switch, a main magnet having a pivoted armature movable by said magnet to close the switch, a supporting strip secured to the armature and extending rearwardly across its free end, a latch pivotally mounted on a fixed support and having a roller at its free end adapted to rest on said strip while the armature is in normal position and movable into position to lock the armature when the latter moves to switch-closing position, and a holding magnet having an armature pivoted to a fixed support and adapted to rock the latch into the locking position when the magnets are energized and to rock the latch away from the locking position when the holding magnet is de-energized.

3. Alternating current switch mechanism 'comprising a normally open switch, a main magnet having a pivoted armature movable by said magnet to close the switch, a supporting strip secured to the armature and extending rearwardly across its free end, a latch pivotally mounted on a fixed support and having a roller at its free end adapted to rest on said strip while the armature is in normal position and.

movable into position to lock the armature when the latter moves to switch-closing position, a holding magnet having an armature pivoted to a fixed support and adapted to rock the latch prising a normally open switch,

into the locking position when the magnets are energized and to rock the locking position when the holding magnet is deenergized, and a switch operable by the latch for opening the circuit of the main magnet when the latch is moved to the locking position.

4. Alternating current switch mechanism coma main magnet having a pivoted armature movable by said magnet to close the switch, a supporting strip secured to the armature and extending rearwardlyacross its free end, a latch pivotally mounted on'a fixed support and having a roller at its free end adapted to rest on said strip while the 1 armature is, in normal position and movable into position. to lock the armature when the latter latch away from the ing position position when the moves to switch-closing position, a holding magnet having an armature pivoted to a fixed support and adapted to rock the latch into the lockwhen the magnets are energized and to rock the latch away from the locking holding magnet is de-energized, and a. switch operable by the latch for opening the circuit of the main magnet when the latch is moved to the locking position, said switch comprising a contact 'member mounted on the free end of the latch and insulated therefrom and a pair of stationary spring contact members normally engaging said first-mentioned member.

JOSEPH F. TRIBE. 

